The purpose of this project is to understand at the molecular level the nature and underlying mechanism of the helix-random coil transition in polypeptides. Relaxation rates for the transition have been obtained using ultrasonic attenuation and dielectric relaxation experiments. In terms of the theoretical model we have developed, it is possible to relate these measured relaxation rates to the molecular rate constants and equilibrium conformational statistics. The results are based upon a general description of the time rate of change of the conformational probabilities in the form of a set of coupled differential equations. We find that the effects of finite chain length are important and that these effects can persist to greater than 1,000 peptide units.